Classical conditioning and extinction of human systolic blood pressure

Fifty-five male and female undergraduates underwent 3 sessions of conditioning and one of extinction. Shock (UCS) occurred intermittently during light-on (CS+) and never in light-off (CS-). Results showed that (1) pressure in CS+ was significantly higher than CS-throughout all sessions; (2) within session adaptation was significantly retarded while incoming pressure levels did not adapt across sessions; (3) conditioned effects persisted 6 months after the last shock session; (4) verbal information as to non-appearance of shock significantly dropped pressure levels and reduced the discriminative light effect; (5) the post-shock unconditioned pressure response was a peak rise at 52 seconds, then a decrease which stabilized to the pre-shock level at 2 minutes. Pavlovian control of blood pressure was demonstrated and the present methodology offers an explicit procedure for further laboratory exploration.